Composite formed body and method for producing same

ABSTRACT

In a molded composite article formed by directly joining a resin member comprising a polyamide-series resin to a resin member comprising a thermoplastic polyurethane-series resin, as the polyamide-series resin, a polyamide-series resin having an amino group of not less than 10 mmol/kg is used. The molded composite article may be produced by heating at least any one of the polyamide-series resin and the thermoplastic polyurethane-series resin to join to the other resin.

TECHNICAL FIELD

The present invention relates to a molded composite article in which aresin member comprising a specific polyamide-series resin is joined to aresin member comprising a thermoplastic polyurethane in a one-piececonstruction without an adhesive, and a process for producing the same.

BACKGROUND ART

In order to improve design or decorative property or to impart excellenttouch or texture (e.g., soft texture), composites (molded compositearticles) formed with a combination of a plurality of resins each havinga different hardness, for example, a molded composite article in whichat least part of a resin molded article is coated with a thermoplasticelastomer, have been proposed. Such a molded composite article isusually produced by adhesion of a plurality of molded members through anadhesive. For example, Japanese Patent Application Laid-Open No.267585/1996 (JP-8-267585A) discloses a resin molded article in which aplurality of resin molded articles formed with a polyamide resin orothers are adhered to each other through a finishing agent such as aurethane polymer or a urethane adhesive. However, such a process usingan adhesive is not only uneconomical due to complicated steps, but alsohas problems such as environmental pollution by an organic solvent orothers.

On the other hand, from the viewpoint of rationalization of productionprocesses or environmental protection, a process for thermal fusing of aplurality of molded members has been adopted. The molded compositearticle obtained by thermal fusing is usually manufactured by a moldingprocess such as a two-color (or double) molding or an insert molding.However, combination of different materials allowing of thermal fusingis significantly limited. Moreover, it is not easy to establish moldingconditions to ensure enough bonded strength. Therefore, in addition tothermal fusing, the fused part is reinforced by a combination use of aprocess for creating a concavo-convex site (or part) in the compositearea of the molded member to join mechanically, or a process for coatinga primer or others on the joining (or fusing) part, or other methods. Insuch a method, however, the molded composite article is deteriorated inflexuous property. For example, the hardened primer layer easily forms acrack by bending. Moreover, the production process needs to complicatethe structure of the molded member, resulting in increase of the numberof the production steps.

In order to solve these problems, it has been investigated to use athermoplastic polyurethane as a material for a resin member constitutinga molded composite article. The thermoplastic polyurethane itself isrelatively excellent in adhesiveness. For example, in a used forshoe(s), a molded composite plastic article comprising a polyamide resinand a thermoplastic polyurethane is practically used as a shoe sole.Moreover, Japanese Patent Application Laid-Open No. 505333/1996(JP-8-505333A) discloses that a lightened shoe sole is obtained byinjection-molding a polyamide elastomer containing a foaming agent intoa mold, inserting or putting a molded article of a thermoplastic resinsuch as a polyether amide, a polyether ester or a polyurethane in amold, and adhering to the thermoplastic resin molded article(un-lightweight (un-lightened) plastic) and the elastomer (lightweightthermoplastic elastomer). Japanese Patent Application Laid-Open No.125155/1995 (JP-7-125155A) discloses a molded composite article in whicha rigid plastic molded member formed of a blended matter of apolypropylene and a polyamide is coated with a nonrigid (or flexible)plastic containing a thermoplastic polyurethane and a plasticizer bythermal fusing. However, even in such a molded composite article (forexample, a molded composite article using a polyurethane resin), theadhesive strength between two materials (e.g., an adhesive strengthrelative to a polyamide elastomer as a counterpart member) has not beenenough yet. Therefore, such a composite is affected by not onlyconditions for molding or conditions of materials to be used (e.g.,production lot) but also environment to be used of the product (moldedcomposite article), resulting in unstableness of the adhesive strengthor the duration of the molded composite article (particularly theduration of the adhered site).

It is therefore an object of the present invention to provide a moldedcomposite article in which, even using a polyamide-series resin memberand a thermoplastic polyurethane-series resin member different incharacter from each other, the both members are directly and firmlyjoined together without an adhesive, and a process for producing thesame.

It is another object of the present invention to provide a process forproducing a molded composite article in which a polyamide-series resinmember and a thermoplastic polyurethane resin member are firmly joinedtogether by thermal fusing in a convenient manner without going throughcomplicated production steps.

DISCLOSURE OF THE INVENTION

The inventors of the present invention made intensive studies to achievethe above objects and finally found that combination use of apolyamide-series resin having a specific content of an amino group and athermoplastic polyurethane-series resin ensures firm joining (orbonding) between a resin member of the polyamide-series resin and aresin members of the polyurethane-series resin. The present inventionwas accomplished based on the above findings.

That is, the molded composite article of the present invention comprises(Ia) a resin member comprising a polyamide-series resin and (IIa) aresin member comprising a thermoplastic polyurethane-series resin, andthe resin member (Ia) is directly joined or bonded to the resin member(IIa), and the polyamide-series resin has an amino group(s) in aproportion of not less than 10 mmol/kg.

The polyamide-series resin constituting the resin member (Ia) may be thefollowing resin (A) or (B):

(A) a polyamide-series resin which is (Ib-1) a single polyamide-seriesresin, or (Ib-2) a mixture of a plurality of polyamide-series resinseach having different amino group content from each other, and which hasan amino group(s) in a proportion of not less than 20 mmol/kg,

(B) a polyamide-series resin which is (Ib-3) a resin compositioncontaining a polyamide-series resin and a compound having an aminogroup(s) (amine compound), and which has an amino group(s) in aproportion of not less than 10 mmol/kg.

Moreover, the polyamide-series resin constituting the resin member (Ia)may be an aliphatic polyamide-series resin, an alicyclicpolyamide-series resin, an aromatic polyamide-series resin, a polyamideblock copolymer, and others. In the resin composition (Ib-3), thecompound having an amino group may be at least one member selected fromthe group consisting of a monoamine, a polyamine, and a polyamideoligomer, and the proportion of the compound having an amino group maybe about 0.01 to 10 parts by weight relative to 100 parts by weight ofthe base polyamide-series resin.

The polyamide-series resin constituting the resin member (Ia) maycomprise a polyamide oligomer, and at least one base polyamide resinselected from the group consisting of an aliphatic polyamide-seriesresin, an alicyclic polyamide-series resin, and a polyamide blockcopolymer. The thermoplastic polyurethane-series resin may comprise athermoplastic polyurethane elastomer.

In the molded composite article, a polyamide-series resin having aterminal amino group, and a thermoplastic polyurethane-series resincomprising a polyester polyurethane obtained from a polyester diol maybe used in combination.

In the molded composite article, (Ib) a polyamide-series resin having anamino group (e.g., a polyamide-series resin comprising at least onemember selected from the group consisting of an aliphaticpolyamide-series resin, an alicyclic polyamide-series resin, and anaromatic polyamide-series resin) may be used in combination with (IIb) athermoplastic polyurethane-series resin comprising at least one memberselected from the group consisting of a polyether urethane elastomer, apolyester ether urethane elastomer, and a polycarbonate urethaneelastomer. Moreover, in the molded composite article, (Ib) apolyamide-series resin comprising at least a polyamide block copolymermay be used in combination with (IIb) a thermoplasticpolyurethane-series resin comprising at least one member selected fromthe group consisting of a polyether urethane elastomer, a polyesterurethane elastomer, a polyester ether urethane elastomer, and apolycarbonate urethane elastomer; and the polyamide block copolymer maybe a polyamide elastomer having in a molecule thereof at least onemember selected from the group consisting of a polyether segment, apolyester segment, and a polycarbonate segment.

The molded composite article of the present invention is, for example,suitable for a member of a shoe or a roll.

Such a molded composite article may be produced by heating at least oneresin selected from the group consisting of (Ib) the resin comprising apolyamide-series resin and (IIb) the resin comprising a thermoplasticpolyurethane-series resin to join one resin to the other resin. Forexample, the thermoplastic polyurethane-series resin may be melted orfused under heating, and the molten thermoplastic polyurethane-seriesresin may be brought into contact with at least part of a resin membercomprising the polyamide-series resin for uniting both resins. Moreover,the polyamide-series resin may be melted or fused under heating, and themolten polyamide-series resin may be brought into contact with at leastpart of a resin member comprising the thermoplastic polyurethane-seriesresin for uniting both resins. Further, the polyamide-series resin andthe thermoplastic polyurethane-series resin may be independently meltedor fused under heating, and the molten polyamide-series resin may bebrought into contact with the molten thermoplastic polyurethane-seriesresin for uniting both resins. Furthermore, the polyamide-series resinand the thermoplastic polyurethane-series resin may be joined and unitedby a molding method selected from the group consisting of athermoforming, an injection molding, an extrusion molding, and a blowmolding.

Incidentally, throughout this specification, the meaning of the term“resin” includes “a resin composition”. Moreover, throughout thisspecification, the term “adhesion (or adhering)” means a technique forcompounding a plurality of members through an adhesive, the term“joining (or bonding)” means a technique for compounding a plurality ofmembers without an adhesive, and the both terms are distinguished fromeach other. Fusing (or thermal fusing) is one embodiment of joining.

DETAILED DESCRIPTION OF THE INVENTION

[Molded Composite Article]

The molded composite article of the present invention comprises (Ia) aresin member comprising a polyamide-series resin, and (IIa) a resinmember comprising a thermoplastic polyurethane-series resin, directlyjoining to the polyamide-series resin member.

(Polyamide-Series Resin)

As the polyamide-series resin, there may be mentioned an aliphaticpolyamide-series resin, an alicyclic polyamide-series resin, an aromaticpolyamide-series resin, or others, and various homopolyamides andcopolyamides may be used.

Among the aliphatic polyamide-series resins, the homopolyamide includesa condensation product of an aliphatic diamine component [e.g., aC₄₋₁₆alkylenediamine such as tetramethylenediamine,hexamethylenediamine, or dodecanediamine (preferably aC₄₋₁₄alkylenediamine, particularly a C₆₋₁₂alkylenediamine)] and analiphatic dicarboxylic acid component [e.g., an alkanedicarboxylic acidhaving about 4 to 20 carbon atoms, such as adipic acid, sebacic acid, ordodecanoic diacid (preferably a C₄₋₁₆alkanedicarboxylic acid, andparticularly a C₆₋₁₄alkanedicarboxylic acid)], for example, a polyamide46, a polyamide 66, a polyamide 610, a polyamide 612, and a polyamide1010; a homopolyamide of a lactam [e.g., alactam having about 4 to 20(preferably about 4 to 16) carbon atoms, such as ε-caprolactam orω-laurolactam] or an aminocarboxylic acid [e.g., an aminocarboxylic acidhaving about 4 to 20 (preferably about 4 to 16) carbon atoms, such asω-aminoundecanoic acid], for example, a polyamide 6, a polyamide 11, anda polyamide 12; and others. Moreover, the copolyamide includes acopolyamide which is obtained by copolymerization of a monomer componentcapable of constituting a polyamide, e.g., the aliphatic diaminecomponents, the aliphatic dicarboxylic acid components, the lactams andthe aminocarboxylic acids. Examples of the copolyamide include acopolymer of 6-aminocaproic acid and 12-aminododecanoic acid; acopolymer of 6-aminocaproic acid, 12-aminododecanoic acid,hexamethylenediamine and adipic acid; a copolymer ofhexamethylenediamine, adipic acid, hydrogenated dimer acid and12-aminododecanoic acid; a polyamide 6/11, a polyamide 6/12, a polyamide66/11, a polyamide 66/12; and others.

The alicyclic polyamide-series resin includes a homopolyamide orcopolyamide having at least one component selected from the groupconsisting of at least an alicyclic diamine and an alicyclicdicarboxylic acid as a constitutive component. For example, there may beused an alicyclic polyamide obtained by using an alicyclic diamineand/or an alicyclic dicarboxylic acid as at least one component among adiamine component and a dicarboxylic acid component each constituting apolyamide-series resin. As the diamine component and the dicarboxylicacid component, the above-mentioned aliphatic diamine(s) and/oraliphatic dicarboxylic acid(s) are preferably used in combination withthe alicyclic diamine (s) and/or alicyclic dicarboxylic acid(s). Such analicyclic polyamide-series resin has high transparency, and is known asa so-called transparent polyamide.

Examples of the alicyclic diamine include a diaminocycloalkane such asdiaminocyclohexane (e.g., a diaminoC₅₋₁₀cycloalkane); abis(aminocycloalkyl)alkane such as bis(4-aminocyclohexyl)methane,bis(4-amino-3-methylcyclohexyl)methane, or2,2-bis(4′-aminocyclohexyl)propane [e.g., abis(aminoC₅₋₈cycloalkyl)C₁₋₁₃alkane]; a hydrogenerated xylylenediamineand others. Moreover, the alicyclic dicarboxylic acid includes acycloalkanedicarboxylic acid such as cyclohexane-1,4-dicarboxylic acidor cyclohexane-1,3-dicarboxylic acid (for example, aC₅₋₁₀cycloalkane-dicarboxylic acid), and others.

Among the alicyclic polyamide-series resins, for example, a condensationproduct (a homo- or copolyamide) of the aliphatic dicarboxylic acid andthe alicyclic diamine is preferred.

The aromatic polyamide-series resin includes a polyamide in which atleast one component of the aliphatic diamine component and the aliphaticdicarboxylic acid component in the above aliphatic polyamide comprisesan aromatic component, for example, a polyamide having an aromaticcomponent in a diamine component [for example, a condensation product ofan aromatic diamine (e.g., metaxylylenediamine) and an aliphaticdicarboxylic acid, such as MXD-6], a polyamide having an aromaticcomponent in a dicarboxylic acid component [e.g., a condensation productof an aliphatic diamine (e.g., trimethylhexamethylenediamine) and anaromatic dicarboxylic acid (e.g., terephthalic acid, isophthalic acid)],and others.

Incidentally, in the polyamide-series resin, a polyamide in which both adiamine component and a dicarboxylic acid component comprise an aromaticcomponent [for example, a fully aromatic amide such as apoly(m-phenyleneisophthalamide) (e.g., Aramid)] may be used incombination.

The polyamide-series resin further includes a polyamide comprising adimer acid as a dicarboxylic acid component, a polyamide in which abranched chain structure is introduced by using a small amount of apolyfunctional polyamine and/or polycarboxylic acid component, amodified polyamide (e.g., a N-alkoxymethylpolyamide), a polyamide blockcopolymer, and a composition thereof, and others.

Examples of the polyamide block copolymer include a polyamide-polyetherblock copolymer, a polyamide-polyester block copolymer, and apolyamide-polycarbonate block copolymer.

In these block copolymers, there may be used, as a block component, adiol component such as an aliphatic diol [for example, an aliphatic diolhaving about 2 to 12 carbonatoms, e.g., a linear (or chain) aliphaticdiol (e.g., ethylene glycol, propylene glycol, tetramethylene glycol,hexanediol, 1,9-nonanediol), and a branched aliphatic diol (e.g.,2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol,2-methyl-1,8-octanediol, 2,2-diethyl-1,3-propanediol)], an alicyclicdiol, and an aromatic diol [for example, a dihydroxyarene which may havea substituent (e.g., a dihydroxyC₆₋₁₂arene such as dihydroxybenzene,dihydroxytoluene, or dihydroxybiphenyl), a bisarylalkane which may havea substituent (e.g., a bis(hydroxyC₆₋₁₀aryl)-chain or branchedC₁₋₄alkane, such as bisphenol A)], and/or a dicarboxylic acid componentsuch as an aliphatic dicarboxylic acid (an alkanedicarboxylic acidhaving about 4 to 20 carbon atoms, such as adipic acid, sebacic acid, ordodecanoic diacid), an alicyclic dicarboxylic acid (acycloalkanedicarboxylic acid having 5 to 10 carbon atoms, such ascyclohexane-1,4-dicarboxylic acid, or cyclohexane-1,3-dicarboxylicacid), and an aromatic dicarboxylic acid (e.g., terephthalic acid,isophthalic acid).

The polyamide-ether block copolymer includes, for example, a polyamidecopolymer having in a molecule thereof a polyether comprising at leastone member selected from the above-mentioned diol components as one of ablock or segment. Moreover, the polyamide-polyester block copolymerincludes a polyamide copolymer having in a molecule thereof a polyesteras one of a block or segment, where the polyester is obtained bypolycondensation of at least one member selected from the diolcomponents and at least one member selected from the dicarboxylic acidcomponents. The polycarbonate-polyamide block copolymer includes apolyamide copolymer having in a molecule thereof a polycarbonate esterof at least one diol selected from the diol components as one of a blockor a segment.

In the polyamide block copolymer, a polyether block, a polyester blockand/or a polycarbonate block which are contained in the copolymer areoften used for the purpose of imparting softness or flexibility to thepolyamide (as a soft block). A polyamide block copolymer having bothsuch a soft block (or soft segment) and a polyamide block (hard block orhard segment) is referred to as a polyamide elastomer.

The polyamide block copolymer is obtained by copolycondensation of apolyamide block having a reactive end group, and any one of a polyetherblock, a polyester block and a polycarbonate block each having areactive end group, or a combination thereof. For example, a polyetherpolyamide block copolymer of a polyether amide-series is obtained bycopolycondensation of a polyamide block having an amino group as the endgroup and a polyoxyalkylene block having a carboxyl group as the endgroup, or by copolycondensation of a polyamide block having a carboxylgroup as the end group and a polyoxyalkylene block having an amino groupas the end group. Moreover, a polyether polyamide block copolymer of apolyether ester amide-series is obtained by polycondensation of apolyamide block having a carboxyl group as the end group and apolyoxyalkylene block having a hydroxyl group as the end group. Thesecopolymers are generally known as a polyamide elastomer. Incidentally,commercially available polyamide elastomers are hardly free from anamino group in many cases. Throughout this specification, the polyamideblock copolymer includes a copolymer obtained by copolycondensation ofthe above-described polyamide block and other block(s) (e.g., apolyether block, a polyester block, a polycarbonate block), in additiona polyamide block copolymer obtained by polyaddition of variousdiisocyanates to at least one of a polyether block, a polyester blockand a polycarbonate block each having carboxyl groups at both ends, ifnecessary under coexistence with the dicarboxylic acid component, anddecarboxylation of the resulting product.

Among the polyamide block copolymers, a polyether polyamide blockcopolymer, in particular a polyamide elastomer containing a polyethersegment as a soft segment, is preferred.

In the polyamide elastomer, the molecular weight (or weight-averagemolecular weight) of the polyoxyalkylene glycol constituting thepolyether segment may for example be selected within a range from about100 to 10000, and may be preferably about 300 to 6000 (e.g., about 300to 5000) and more preferably about 500 to 4000 (e.g., about 500 to3000).

Incidentally, the proportion of the polyether segment in the polyamideelastomer may for example be about 10 to 90 wt. % (e.g., about 10 to 80wt. %), preferably about 20 to 90 wt. % (e.g., about 20 to 75 wt. %),and more preferably about 30 to 90 wt. % (e.g., about 30 to 70 wt. %)relative to the whole polyamide-series resin (or composition)constituting the resin member. Moreover, in the polyamide elastomer, theratio (weight ratio) of the polyamide segment relative to the polyethersegment (e.g., a PTMG segment) is not particularly limited to a specificone, and for example, the former/the latter may be about 9/1 to 2/8,preferably about 9/1 to 2.5/7.5, more preferably about 8/2 to 3/7, andparticularly 7/3 to 4/6.

The polyamide-series resin(s) may be used singly or in combination.Moreover, the polyamide-series resin may be a blend or alloy comprisinga plurality of polyamide-series resins.

The preferred polyamide-series resin includes the aliphaticpolyamide-series resin, the alicyclic polyamide-series resin (inparticular, the transparent polyamide), and others. These preferredpolyamide-series resins may be used in combination with the aromaticpolyamide-series resin. Further, the polyamide block copolymer(polyamide elastomer) is also preferred.

The number average molecular weight of the polyamide-series resin isabout 6,000 to 100,000, preferably about 8,000 to 50,000, and morepreferably about 10,000 to 30,000.

In the present invention, the polyamide-series resin (or resincomposition) (Ib) constituting the resin member (Ia) has an amino groupat a specific concentration. The amino group usually shows a free aminogroup (—NH₂ group) and usually does not include a —NH— (imino) group and—N< group derived from an amide bond constituting the main chain of thepolyamide-series resin, a urea bond, a urethane bond and other bond. Thepolyamide-series resin may have the free amino group in a branched chainthereof, or at the end of a main chain thereof.

The content (or concentration) of the amino group (or amino groupconcentration) in the polyamide-series resin (or containing a resincomposition) (Ib) is, relative to 1 kg of the polyamide-series resin(Ib), not less than 10 mmol (e.g., about 10 to 300 mmol), preferably notless than 15 mmol (e.g., about 15 to 200 mmol), more preferably not lessthan 20 mmol (e.g., about 20 to 150 mmol), and particularly not lessthan 30 mmol (e.g., about 30 to 100 mmol). Moreover, the concentrationmay for example be about 35 to 300 mmol, preferably about 40 to 200mmol, and more preferably about 50 to 150 mmol relative to 1 kg of thepolyamide-series resin (Ib). In particular, the polyamide-series resin(Ib) preferably contains a terminal amino group at a range of such acontent.

The content of the amino group may be adjusted by a conventional method,for example, (a) a method of adjusting a proportion of a diaminecomponent constituting a polyamide-series resin; (b) a method of forminga blend or alloy by combining a plurality of polyamide-series resinsdifferent in amino group concentration from each other (e.g. by using apolyamide-series resin having an amino group at a low concentration incombination with a polyamide-series resin having an amino group at ahigh concentration); and (c) a method of involving a compound having anamino group (e.g., an amino group-containing compound having an aminogroup at a high concentration and having a relatively low molecularweight) in a polyamide-series resin (e.g., a polyamide having an aminogroup at a low concentration, such as the polyamide block copolymer(e.g., a polyamide elastomer) described above). For example, in acopolycondensation of a block having amino groups at the both ends and ablock having carboxyl groups at the both ends, introduction of an aminogroup into the polyamide block copolymer (e.g., a polyamide elastomer)may be conducted by increasing the proportion of the block having aminogroups at the both ends, or by adding an amino group-containing compoundmiscible with a polyamide-series resin at an adequate amount in additionto the polyamide-series resin.

In the case where the polyamide-series resin comprises only a polyamideresin (Ib-1), the amino group concentration may be adjusted by a methodsuch as the above-mentioned method (a). Moreover, in the case where thepolyamide-series resin is a mixture (Ib-2) containing a plurality ofpolyamide-series resins and prepared by the above-mentioned method (b),the amino group concentration of each polyamide-series resin may besuitably adjusted by the method (a) and/or (c) described above.

When the polyamide-series resin is a single polyamide-series resin(e.g., a resin prepared by the method (a)), or a mixture containing aplurality of polyamide-series resins different in amino groupconcentration from each other (e.g., a mixture prepared by the method(b)), the amino group concentration of the polyamide-series resin (orcomposition) (Ib) may for example be not less than 20 mmol/kg (e.g.,about 20 to 300 mmol/kg), preferably not less than 30 mmol/kg (e.g.,about 30 to 200 mmol/kg), more preferably not less than 40 mmol/kg(e.g., about 40 to 150 mmol/kg), and particularly not less than 50mmol/kg (e.g., about 50 to 100 mmol/kg).

In the case using a plurality of polyamide-series resins different inamino group concentration from each other in combination, the totalcontent of the amino group in the polyamide-series resins may forexample be adjusted by using a polyamide-series resin having an aminogroup concentration of about 0 to 30 mmol/kg (e.g., about 0 to 20mmol/kg) in combination with a polyamide-series resin having an aminogroup concentration of about 40 to 400 mmol/kg (preferably about 50 to300 mmol/kg, and particularly about 100 to 200 mmol/kg). The proportionof the polyamide-series resin having an amino group at a higherconcentration may be such a proportion that the mean concentration ofthe amino group corresponds to the above-mentioned amino groupconcentration, and may for example be about 1 to 60 parts by weight,preferably about 5 to 50 parts by weight, and more preferably about 10to 40 parts by weight relative to 100 parts by weight of thepolyamide-series resin having an amino group at a lower concentration.

In the case where the polyamide-series resin (Ib) is a resin compositioncomprising a polyamide-series resin and an amino group-containingcompound (e.g., (Ib-3) a composition prepared by the method (c)), theamino group concentration of the polyamide-series resin (Ib) may forexample be not less than 10 mmol/kg (e.g., about 10 to 300 mmol/kg),preferably not less than 20 mmol/kg (e.g., about 20 to 200 mmol/kg),more preferably not less than 30 mmol/kg (e.g., about 30 to 150mmol/kg), and particularly not less than 40 mmol/kg (e.g., about 40 to100 mmol/kg).

As the amino group-containing compound, there may be used an aminogroup-containing compound having a relatively low molecular weight, suchas a polyamine [a diamine (for example, the above-mentioned aliphaticdiamines, alicyclic diamines and aromatic diamines), in addition apolyamine, for example, an aliphatic polyamine such as apolyalkylenepolyamine such as diethylenetriamine, ortriethylenetetramine (e.g., a polyC₂₋₃alkylenepolyamine)], a monoamine,and a polyamide oligomer. The amino group-containing compound(s) may beused singly or in combination. Among these compounds, the polyamideoligomer is preferred from the viewpoint of joining (or bonding)property.

As the polyamide oligomer, there may be used a polyamide having arelatively low molecular weight, which is obtained by a conventionalmanner, for example, by adjusting polycondensation or other conditionsand using the above-mentioned polyamide component(s). For example, as apolyamide component to be a raw material, there may be mentioned thecombination of the above-mentioned diamine [e.g., an aliphatic diamine(e.g., an alkylenediamine), an alicyclic diamine, an aromatic diamine]and a dicarboxylic acid (e.g., an aliphatic dicarboxylic acid, anaromatic dicarboxylic acid), the combination of the above-mentioneddiamine and/or dicarboxylic acid and the lactam (e.g., a lactam havingabout 4 to 20 carbon atoms, such as ω-laurolactam), and othercombinations. The polyamide oligomer may be obtained by for examplepolymerizing the lactam and the aliphatic diamine with heating andstirring under an applied pressure.

The number average molecular weight of the polyamide oligomer is, forexample, about 500 to 10,000, preferably about 500 to 8,000 (e.g., about1,000 to 7,000), more preferably about 1,000 to 5,000, and usually about2,000 to 6,000 (e.g., about 3,000 to 6,000). Moreover, the joiningproperty of the polyamide-series resin constituting the resin member tothe thermoplastic polyurethane can be improved by using a polyamideoligomer having a relatively high molecular weight, for example, thenumber average molecular weight of about 1000 to 10,000, preferablyabout 2,000 to 9,000, and more preferably about 3,000 to 8,000.

The polyamide oligomer usually may not have a free amino group, or mayhave a free amino group. In the case where the polyamide oligomer has afree amino group, the amino group may be located in at least one end ofa main chain, in both ends of a main chain, or in a branched chain (s).

The amino group-containing compound (particularly a polyamide oligomer)may be used in combination with a resin such as the aliphaticpolyamide-series resin, the alicyclic polyamide-series resin or thepolyamide block copolymer, as a base polyamide resin.

In the case where the polyamide-series resin is composed of an aminogroup-containing compound and a base polyamide resin in combination, forexample, the total content of the amino group in the polyamide-seriesresin (or composition) may be adjusted by using a polyamide-series resinhaving an amino group concentration of about 0 to 30 mmol/kg (preferablyabout 0 to 20 mmol/kg) in combination with an amino group-containingcompound having an amino group concentration of about 40 to 1000 mmol/kg(preferably about 50 to 700 mmol/kg, and particularly about 100 to 500mmol/kg).

The proportion of the amino group-containing compound may be controlledso that the content of the amino group in the polyamide-series resin(Ib) is included in the range described above. For example, theproportion of the amino group-containing compound (e.g., the polyamideoligomer) is, for example, not more than 10 parts by weight (about 0.01to 10 parts by weight), preferably about 0.1 to 8 parts by weight, andparticularly not more than 7 parts by weight (about 0.5 to 7 parts byweight) relative to 100 parts by weight of the base polyamide resin (apolyamide-series resin having an amino group at a low concentration). Inthe case where the proportion of the amino group-containing compound istoo large, there is a possibility that use of the polyamide-series resin(Ib) particularly as a hard resin deteriorates resin property thereof.

In order to further enhance the bonded strength between thepolyamide-series resin member (Ia) (e.g., a hard resin member) and thethermoplastic polyurethane-series resin member (IIa) (e.g., a soft resinmember), the enthalpies of fusion and crystallization of thepolyamide-series resin (Ib) may be not more than 100 J/g (e.g., about 0to 100 J/g), preferably not more than 80 J/g (e.g., about 0 to 80 J/g),and more preferably not more than 70 J/g (e.g., about 0 to 70 J/g).According to the present invention, even using a polyamide-series resinhaving a low degree of crystallinity, certain and efficient joining canbe ensured. The enthalpies of fusion and crystallization in such apolyamide-series resin may for example be selected from a range of notmore than 30 J/g (e.g., about 0 to 30 J/g), preferably not more than 20J/g (e.g., about 0 to 20 J/g), and more preferably not more than 17 J/g(about 0 to 17 J/g).

The “enthalpies of fusion and crystallization” of the polyamide-seriesresin means a value obtained by subtracting a heat of crystallization(ΔHf) generated along with crystallization of a resin from a heat offusion (ΔHm) necessary to melt the resin. That is, in a measurement ofthe heat of fusion, if both the heat of crystallization and thefollowing heat of fusion are observed along with raising thetemperature, the enthalpies of fusion and crystallization of thepolyamide-series resin is assessed as a value subtracted the found valueΔHf of the heat of crystallization per one gram of the resin from thefound value ΔHm of the heat of fusion per one gram of the resin. Theenthalpies of fusion and crystallization can be measured by adifferential scanning calorimeter (DSC apparatus) based on JIS (JapaneseIndustrial Standards) K 7122. Incidentally, since the heat ofcrystallization cannot be observed in a fully amorphous polyamide, theenthalpies of fusion and crystallization of such a polyamide isqualified as 0 J/g.

The polyamide-series resin having such enthalpies of fusion andcrystallization, in particular a polyamide-series resin havingenthalpies of fusion and crystallization of not more than 20 J/g (e.g.,a transparent polyamide) may be molded by a known molding method. Thefurther details about of such a polyamide-series resin may for examplebe referred to Japanese Patent Application Laid-Open No. 239469/1996(JP-8-239469A), Japanese Patent Application Laid-Open No. 1544/2000(JP-2000-1544A), and others.

Incidentally, the concentration of the carboxyl group (or carboxyl groupconcentration) in the polyamide-series resin (Ib) is not particularlylimited to a specific one, and may for example be about 0.1 to 200mmol/kg, preferably about 0.5 to 150 mmol/kg, and more preferably about1 to 100 mmol/kg.

In such a range that the effects of the present invention are notdeteriorated, the polyamide-series resin member may comprise otherresin(s) [for example, a thermoplastic resin such as a polyester-seriesresin, a polycarbonate-series resin, a polysulfone-series resin, apolyimide-series resin, a polyketone-series resin, a polyolefinic resin,a styrenic resin, a (meth)acrylic resin, or a halogen-containingvinyl-series resin)], various additives [for example, a filler orreinforcing agent (e.g., a reinforcing fiber), a stabilizer (e.g., aultraviolet ray absorbing agent, an antioxidant, a heat stabilizer), acoloring agent, a plasticizer, a lubricant, a flame retardant, and anantistatic agent].

Incidentally, in accordance with the production of the molded compositearticle of the present invention, a “warp” sometimes occurs in theproduct depending on the difference between mold shrinkage factors ofthe resin members. In the case where the degree of the correction forthe warp is large, there is a possibility that breaking of the joiningpart or generation of stress crack in each resin member occurs.Therefore, the polyamide-series resin preferably has lowercrystallinity. The final crystallinity degree (mean final crystallinitydegree) of the polyamide-series resin is advantageously not more than50% (e.g., about 5 to 50%), preferably not more than 40% (e.g., about 5to 40%), and more preferably not more than 30% (e.g., about 10 to 30%).In the case where a polyamide homopolymer is taken as an example and thefinal crystallinity degree is compared, the final crystallinity degreebecomes smaller in the following order.

polyamide 66>polyamide 6≧polyamide 612>polyamide 11≧polyamide 12

Incidentally, considering only the final crystallinity degree, thecopolymer is more advantageous than the homopolymer. Further, in generalthe copolymer is also more advantageous than the homopolymer from theperspective that the copolymer is superior to the homopolymer inflexibility.

It is found that, in the case of a polyamide block copolymer (apolyamide elastomer) which comprises a polyamide as a hard segment and apolyether, a polyester, or a polycarbonate or others as a soft segment,the final crystallinity degree can be adjusted by the ratio of the hardsegment and the soft segment. For example, in the case where a softsegment is a polyether, large relative ratio of a polyether segmentrelative to a polyamide block makes the final crystallinity degreelower. Moreover, in the case comprising a branched diol as a diolcomponent constituting a soft segment, the larger the relative ratio is,the lower the final crystallinity is. Through the use of this technique,when the final crystallinity degree of the polyamide block copolymer isadjusted to not more than 40% (e.g., about 5 to 40%), preferably notmore than 35% (e.g., about 5 to 35%) and more preferably not more than30% (e.g., about 10 to 30%), such a copolymer is advantageously used incombination with a thermoplastic polyurethane-series resin member forinhibiting warp generation, and further can provide a flexibility whichsuits with that of a thermoplastic polyurethane-series resin.

Therefore, the polyamide block copolymer (particularly, the polyamideelastomer) as the polyamide-series resin has an advantage over apolyamide homopolymer from the viewpoint of inhibiting a warp in themolded composite article. In particular, it is advantageous when themolded composite article is obtained by molding the polyurethane-seriesresin member (IIa) firstly, and thereafter molding the polyamide-seriesresin member (Ia) (for example, in injection molding, overmolding of apolyamide resin to an insert of a polyurethane resin molded article, andin extrusion molding, lamination or coating of a polyamide resin to apolyurethane molded article).

Incidentally, the term “the final crystallinity degree” means a degreeof crystallinity measured by an X-ray diffraction analysis using a flatplate 1 mm thick, where the flat plate is formed by heating a sampleresin to a temperature which is 20° C. higher than a melting pointthereof, and then cooling the resin to a room temperature at a rate of3° C./minute by means of a precision (or accurate) heat pressingmachine. The melting point of the resin is measured by a differentialscanning calorimeter (DSC apparatus) in accordance with JIS K 7122.

In the case where the polyamide-series resin (Ib) comprises a polyamideelastomer, high bonded strength is ensured. In particular, in the caseforming a molded composite article by bringing a molten thermoplasticpolyurethane-series resin (or composition) (IIb) into contact with aresin member comprising a polyamide elastomer by injection molding orother means, the polyamide-series resin member and thepolyurethane-series resin member are firmly joined together, and highbonded strength can be obtained easier than the case using the polyamidehomopolymer as a polyamide-series resin. In this case, there is acertain correlation between the bonded strength and the amount of thesoft segment (e.g., a polyether segment) contained in the polyamideelastomer, and the amount of the soft segment relative to the polymermay be not less than 10 wt. % (e.g., about 10 to 90 wt. %), morepreferably not less than 20 wt. % (e.g., about 20 to 70 wt. %), and morepreferably not less than 25 wt. % (e.g., about 25 to 65 wt. %).

(Polyurethane-Series Resin)

The thermoplastic polyurethane-series resin may be obtained by reactinga diisocyanate, a diol and, if necessary, a chain-extension agent.

The diisocyanate includes an aliphatic diisocyanate such ashexamethylene diisocyanate (HMDI), or 2,2,4-trimethylhexamethylenediisocyanate; an alicyclic diisocyanate such as 1,4-cyclohexanediisocyanate, dicycloalkylmethane-4,4′-diisocyanate, or isophoronediisocyanate (IPDI); an aromatic diisocyanate such as phenylenediisocyanate, tolylene diisocyanate (TDI), ordiphenylmethane-4,4′-diisocyanate (MDI); an araliphatic diisocyanatesuch as xylylene diisocyanate; and others. As the diisocyanate, theremay also be used a compound having an alkyl group (e.g., methyl group)substituted on a main chain or ring thereof. The diisocyanate(s) may beused singly or in combination.

Examples of the diol include a polyester diol [for example, a polyesterdiol (aliphatic polyester diol) derived from an aliphatic dicarboxylicacid component (e.g., a C₄₋₁₂aliphatic dicarboxylic acid such as adipicacid), an aliphatic diol component (e.g., a C₂₋₁₂aliphatic diol such asethylene glycol, propylene glycol, butanediol, or neopentyl glycol),and/or a lactone component (e.g., a C₄₋₁₂lactone such asε-caprolactone), e.g., a poly(ethylene adipate), a poly(1,4-butyleneadipate), and a poly(1,6-hexylene adipate), a poly-ε-caprolactone], apolyether diol [for example, an aliphatic polyether diol, e.g., apoly(oxyC₂₋₄alkylene) glycol such as a polyethylene glycol, apoly(oxytrimethylene) glycol, a polypropylene glycol, or apolytetramethylene ether glycol (PTMG), and a block copolymer of thepoly(oxyalkylene) glycol (e.g., a polyoxyethylene-polyoxypropylene blockcopolymer); an aromatic polyether diol, e.g., an adduct of an aromaticdiol with an alkylene oxide, such as a bisphenol A-alkylene oxide adduct(e.g., an adduct of a C₂₋₄alkylene oxide such as ethylene oxide, orpropylene oxide)]; a polyester ether diol (a polyester diol obtained byusing the polyether diol as part of a diol component); a polycarbonatediol; and others. The diol(s) may be used singly or in combination.Among these diols, the polyester diol, or the polyether diol such as apolytetramethylene ether glycol (e.g., a polyester diol) is used in manycases.

As the chain-extension agent, there may be used a glycol [for example, ashort chain glycol, e.g., a C₂₋₁₀alkanediol such as ethylene glycol,propylene glycol, 1,4-butanediol, or 1,6-hexanediol; abishydroxyethoxybenzene (BHEB)], and in addition a diamine [for example,an aliphatic diamine such as a C₂₋₁₀alkylenediamine, e.g.,ethylenediamine, trimethylenediamine, tetramethylenediamine, orhexamethylenediamine; an alicyclic diamine such as isophorone diamine;an aromatic diamine such as phenylenediamine, or xylylenediamine]. Thechain-extension agent(s) may be used singly or in combination.

The thermoplastic polyurethane-series resin also includes a perfectthermoplastic polyurethane obtained by using a diol and a diisocyanateat a substantially equivalent amount, and an imperfect thermoplasticpolyisocyanate having a small amount of a residual free (or unreacted)isocyanate, which is obtained by using a slightly excess amount of adiisocyanate relative to a diol.

Among the thermoplastic polyurethane-series resins, in particular, thethermoplastic polyurethane elastomer is preferred, which is obtained byusing a diol [e.g., a diol having a polyester unit or a polyether unit(the above-mentioned polyester diol or polyether diol)], a diisocyanate,and a glycol (e.g., a short chain glycol) as the chain-extension agent.The thermoplastic polyurethane elastomer comprises a hard segment (hardblock) which is composed of a polyurethane with the use of a glycol anda diisocyanate, and a soft segment (soft block) composed of a polyetherdiol [for example, an aliphatic polyether diol (e.g., apoly(oxyethylene) glycol)], a polyester diol (e.g., an aliphaticpolyester diol) or others. The polyurethane elastomer includes, forexample, a polyester urethane elastomer, a polyester ether urethaneelastomer, a polyether urethane elastomer, a polycarbonate urethaneelastomer, and others depending on the species of the soft segment.Among the polyurethane elastomers, the polyester urethane elastomer, thepolyester ether urethane elastomer, the polyether urethane elastomer andothers are preferred. Incidentally, the molecular weight (orweight-average molecular weight) of the polyether (polyoxyalkyleneglycol) may for example be selected within a range from about 100 to10000, and may be preferably about 300 to 6000 (e.g., about 300 to5000), and more preferably about 500 to 4000 (e.g., about 500 to 3000).

The thermoplastic polyurethane-series resin(s) may be used singly or incombination.

In the case using a polyamide-series resin (including a composition)having a terminal amino group as the polyamide-series resin (Ib), apolyester polyurethane obtained from a polyester diol, in particular apolyester urethane elastomer may be used as the thermoplasticpolyurethane-series resin.

In the present invention, high bonded strength is ensured by using (Ib)a polyamide-series resin (including a composition) having an amino group(e.g., a polyamide-series resin comprising at least one member selectedfrom the group consisting of an aliphatic polyamide-series resin, analicyclic polyamide-series resin, and an aromatic polyamide-seriesresin) in combination with (IIb) a thermoplastic polyurethane-seriesresin comprising at least one member selected from the group consistingof a polyether urethane elastomer, and a polyester ether urethaneelastomer.

Moreover, (Ib) a polyamide-series resin (including a compositioncontaining a polyamide oligomer) which contains at least a polyamideblock copolymer, e.g., a polyamide elastomer may be used in combinationwith (IIb) a thermoplastic polyurethane-series resin comprising at leastone member selected from the group consisting of a polyether urethaneelastomer, a polyester urethane elastomer, and a polyester etherurethane elastomer.

In such a range that the effects of the present invention are notdeteriorated, the thermoplastic polyurethane-series resin member maycomprise other resin(s) (e.g., a thermoplastic resin, particularly athermoplastic elastomer such as a polyamide-series elastomer, apolyester-series elastomer, or a polyolefinic elastomer), a stabilizer(e.g., a heat stabilizer, an ultraviolet ray absorbing agent, anantioxidant), a plasticizer, a lubricant, a filler, a coloring agent, aflame retardant, an antistatic agent, and others.

In such a molded composite article, since the polyamide-series resin hasa specific amino group concentration, the polyamide-series resin and thethermoplastic polyurethane-series resin are firmly joined togetherwithout an additive. The bonded strength is usually not less than 30N/cm, and cohesive failure sometimes occurs along with separation of thepolyamide-series resin member (e.g., a hard resin member) from thethermoplastic polyurethane-series resin member (e.g., a soft resinmember). The bonded strength of such a molded composite article isusually 30 N/cm to cohesive failure, preferably not less than 40 N/cm,and particularly not less than 50 N/cm (not less than 50 N/cm tocohesive failure).

[Production Process of Molded Composite Article]

The molded composite article of the present invention may be produced byjoining (Ib) the polyamide-series resin (a resin comprising thepolyamide-series resin) to (IIb) the thermoplastic polyurethane-seriesresin (a resin comprising the polyurethane-series resin) under heating.The joining may be usually ensured by heating and melting at least oneresin of (Ib) the polyamide-series resin and (IIb) the thermoplasticpolyurethane-series resin, and bringing the both resins into contactwith each other. Such a molded composite article may for example beproduced by joining the polyamide-series resin to the thermoplasticpolyurethane-series resin in a molding process by means of aconventional method such as a thermoforming (e.g., a heat press molding,an injection press molding), an injection molding (e.g., an insertinjection molding, a two-color (or double) injection molding, acore-back injection molding, a sandwich injection molding), an extrusionmolding (e.g., a co-extrusion molding, a T-die lamination molding), or ablow molding.

For example, in a molding method such as an insert molding or aninjection press molding, the both resins may be joined together byheating and melting the thermoplastic polyurethane-series resin (IIb),and molding the thermoplastic polyurethane-series resin in a moltenstate with contacting with at least part of a resin member (Ia) composedof the polyamide-series resin. The both resins may also be joinedtogether by heating and melting the polyamide-series resin, and moldingthe polyamide-series resin (Ib) in a molten state with contacting withat least part of a resin member (IIa) composed of the thermoplasticpolyurethane-series resin. Moreover, in a molding method such as adouble injection molding or a co-extrusion molding, joining of the bothresins may be ensured by heating and melting both the polyamide-seriesresin (Ib) and the thermoplastic polyurethane-series resin (I Ib)differently, and molding the molten polyamide-series resin and themolten thermoplastic polyurethane-series resin with contacting with eachother. A molded composite article in which the polyamide-series resinmember (Ia) is firmly joined to the polyurethane-series resin member(IIa) can be obtained by melting at least one resin selected from thepolyamide-series resin and the polyurethane-series resin, bringing thepolyamide-series resin into contact with the thermoplasticpolyurethane-series resin for joining, and usually cooling the resultingmatter. Moreover, depending on a purpose and an application, it issufficient to join the polyamide-series resin member to thethermoplastic polyurethane-series resin member at least in part.

Incidentally, the resin can be molten by heating to a temperature of notless than a melting point thereof. In the case of a substantiallyuncrystallized resin, the resin can be molten by heating to atemperature of not less than a glass transition point (Tg) thereof.

According to the present invention, since the polyamide-series resincontains an amino group and the amino group acts (chemically acts) onthe thermoplastic polyurethane-series resin, the bonded strength can besignificantly improved even in a molded composite article obtained froma different kind of materials. Accordingly the present invention ensuressuch a high-level bonded strength that cannot be obtained from aphysical action due to simple thermal fusing. Therefore, throughout ofthis specification, “thermal fusing” includes not only simple thermalfusing, but also thermal fusing (thermal joining) including a chemicalreaction.

As described above, it is not particularly limited which of the resinsbetween the polyamide-series resin and the polyurethane-series resin ismolten. A soft resin (the polyurethane-series resin) having a usuallylower melting point or glass transition point (Tg) may be heated, andjoined to a hard resin member comprising a hard resin (thepolyamide-series resin) having a higher melting point or Tg. Moreover, ahard resin (the polyamide-series resin) having a generally highermelting point or Tg may be heated, and joined to a soft resin membercomprising a soft resin (the polyurethane-series resin) having a lowermelting point or Tg.

Among these methods, in particular, the former method has an advantageover conventional techniques since the effects of the present inventionare characteristically and effectively exhibited. In the conventionalmethod using simple physical thermal fusing, when letting a precedentlymolded polyamide-series resin member joined with a followingly moldingpolyurethane-series resin, the molding temperature of thepolyurethane-series resin becomes lower than the melting point of theprecedently molded polyamide-series resin in many cases, and thereforethermal fusing is difficult to proceed. Moreover, even when the moldingtemperature of the polyurethane-series resin is higher than the meltingpoint of the polyamide-series resin, the heat quantity is ofteninsufficient to melt the surface of the polyamide-series resin member.Therefore, the conventional techniques usually never comprise such amanner as molding the polyamide-series resin member before molding thepolyurethane-series resin. However, even in such a case, since thepolyamide-series resin member and the thermoplastic polyurethane-seriesresin can be more easily joined together by an action of the amino groupcontained in the polyamide-series resin, the present invention canincrease the freedom of the production process of the molded compositearticle and can also rationalize the process step to a large degree.

In the present invention, although the hard resin usually comprises thepolyamide-series resin and the soft resin usually comprises thethermoplastic polyurethane-series resin in practical cases, the hardresin may comprise the thermoplastic polyurethane-series resin and thesoft resin may comprise the polyamide-series resin. Moreover, thehardness of the polyamide-series resin may be the same level as that ofthe thermoplastic polyurethane-series resin.

To be more precise, in the heat press molding, a molded compositearticle may be produced by melting at least one resin of the hard resin(or composition) and the soft resin (or composition) in a metal mold ofthe press molding, bringing the both resins into contact with each otherunder an applied pressure, and joining the resins to each other. In theheat press molding, the hard resin and/or the soft resin may be filledin the metal mold in a pellet form, a powdered form or other form(s), ormay be loaded to the metal mold as a molded article precedently formedby other molding method.

In the insert injection molding, a molded composite article may beproduced by molding any one of the hard resin (or resin composition) orthe soft resin (or resin composition) with the use of a molding method(such as an injection molding, an extrusion molding, a sheet molding, ora film molding), inserting or putting thus shaped molded article in ametal mold, and then injecting the other resin to the space or cavitybetween the molded article and the metal mold. In the insert injectionmolding, the molded article to be inserted in the metal mold ispreferably pre-heated.

In the two-color (or double) injection molding, a molded compositearticle may be produced by injecting any one component of the hard resin(or resin composition) or the soft resin (or resin composition) to ametal mold by means of two injection molding machines or more, andexchanging cavity of the metal mold by rotation or movement of the metalmold, and injecting the other component to the space or cavity betweenthus obtained molded article and the metal mold.

In the core-back injection molding, a molded composite article may beproduced by injecting any one component of the hard resin (or resincomposition) or the soft resin (or resin composition) in a metal mold,enlarging the cavity of the metal mold, and injecting the othercomponent to the space or cavity between thus obtained molded articleand the metal mold.

Among these molding methods, particularly from the viewpoint of massproduction or other properties, suitable methods are, for example, theheat press molding such as injection press molding, and the injectionmolding (e.g., insert injection molding, double injection molding,core-back injection molding, sandwich injection molding).

In the thermal fusing, the melting temperature (or thermal fusingtemperature) of the hard resin and/or soft resin may be selecteddepending on the species of the both resins (or resin compositions), andmay for example be selected within a range of about 100 to 300° C.,preferably about 120 to 290° C., and more preferably about 150 to 280°C. For example, in the heat press molding, the melting temperature maybe about 100 to 250° C., preferably about 120 to 230° C., and morepreferably about 150 to 220° C. Moreover, in the injection molding, thetemperature of the resin in the molding cylinder may for example beabout 200 to 300° C., preferably about 220 to 280° C., and morepreferably about 240 to 280° C.

The structure and configuration of the molded composite article is notparticularly limited to a specific one, and may be a structure suitablefor design, decorative property, touch or others. For example, such astructure may be obtained by coating or laminating part or all of thesoft resin member with the hard resin member, and usually, preferablyobtained by coating or laminating part or all of the hard resin memberwith the soft resin member (for example, obtained by coating part of thehard resin member, which contact with human body (such as a hand), withthe soft resin member). Moreover, the concrete structure includes, forexample, a two-dimensional structure (such as a sheet-like form, or aplate-like form), and a three-dimensional structure (such as astick-like form, a tube-like form, a casing, or a housing).

According to the present invention, the hard resin and the soft resincan be directly and firmly joined together by thermal fusing without(going through) complicated production steps (e.g., a step for creatinga concavo-convex site in the composite area, a step for coating anadhesive). Therefore, the present invention ensures to obtain alightweight and strong molded composite article improved in propertiessuch as design, decorative property, or good touch or texture (e.g.,soft texture, flexibility).

According to the present invention, since a specific polyamide-seriesresin is used in combination with a thermoplastic polyurethane-seriesresin, even a polyamide-series resin member and a thermoplasticpolyurethane-series resin member different in character from each othercan be directly and firmly joined together without an adhesive.Moreover, the present invention ensures to produce a molded compositearticle in which a polyamide-series resin member and a thermoplasticpolyurethane resin member are firmly joined together by thermal fusingin a convenient manner without going through complicated productionsteps.

INDUSTRIAL APPLICABILITY

The molded composite article of the present invention may be used asvarious industrial components (or parts), for example, an automotivepart (e.g., an automotive interior part such as an instrument panel, acenter panel, a center console box, a door trim, a pillar, an assistgrip, a steering wheel, or an air bag cover; an automotive exterior partsuch as a lacing, or a bumper; an automotive functional component suchas a rack and pinion boot, a suspension boot, or a constant velocityjoint boot), a household electrical part (e.g., a cleaner bumper, aswitch of a remote control, a key top of office automation (OA)apparatus), a product to be used in water (e.g., swimming goggles, acover of a underwater camera), an industrial part (a cover part; variousindustrial parts equipped with a packing for the purpose of sealingproperty, water proofing property, sound insulating property, vibrationinsulating property, or other properties; an industrial rubber roller)an electric or electronic device part (e.g., a curl cord wire covering,a belt, a hose, a tube, a sound deadening gear), sports goods, shoesgoods (e.g., athletic shoes, a shoe sole), and a part requiring designor decorative property (e.g., dark glasses, glasses).

Among them, the molded composite article is particularly suitable for aconstitutive member of the shoe or the roll (e.g., a rubber roller). Theconstitutive member of the shoe includes a shoe part such as a shoe sole(sole), or a shoe upper, and others. Moreover, the molded compositearticle may form (or constitute) athletic shoes, work shoes (e.g.,boots, rain shoes, shoes for gardening). In such a shoe application,since a combination of a hard or glass fiber-reinforced polyamide-seriesresin and a soft polyurethane-series resin, which was difficult in thepast, becomes easy, it is, for example, possible to compound differentgrades of materials in many layers. Accordingly, the molded compositearticle greatly contributes to improvement in design or functionality ofthe shoe.

Further, in the roll (e.g., a rubber roller) application, for example,the roll may comprise an axis (shaft) in which at least the surfacelayer comprises a polyamide-series resin, and a thermoplasticpolyurethane-series resin layer formed along the surrounding surface ofthe axis. The axis may be obtained by forming a polyamide-series resinlayer on the surface of the metal shaft, or may be an axis comprising apolyamide-series resin. In such a roller application, since a cuttingfinish for obtaining a shaft precision and a surface finish of athermoplastic polyurethane-series resin can be conducted in oneoperation by the same grinding machine, the production process of theroller can be significantly abbreviated and the cost can beexponentially reduced. Moreover, since such a roller given by chemicallyjoining has high bonded strength and merely has the space or cavitybetween the axis and the roll, the roller can tolerate the usage in ahigh torque.

EXAMPLES

The following examples are intended to describe this invention infurther detail and should by no means be interpreted as defining thescope of the invention.

(Evaluation of Thermal Fusing)

Molded composite articles obtained by Examples and Comparative Exampleswere cut into a size of 20 mm in width and 100 mm in length,respectively. In each cut piece, the tensile test was conducted bydrawing the tong hold to 180° direction at a drawn speed of 20 mm/minuteto determine a peel strength in the fusing interface. On the basis ofthe peel strength, the thermal fusing property between a hard resinmember and a soft resin member was evaluated.

Example 1

To an aqueous solution (1250 g) containing a salt ofhexamethylenediamine with dodecanedicarboxylic acid in a concentrationof 80% by weight was added 7 g of hexamethylenediamine. The resultingmixture was heated at 220° C. under an applied pressure (inner pressure)(17.5 kgf/cm (1.7×10⁶ Pa)) in an autoclave substituted with nitrogengas, and water was flowed out with the nitrogen gas from the reactionsystem for 4 hours. Subsequently, the temperature of the system wasgradually increased up to 275° C. over 1 hour, and water remaining inthe system was removed out of the system. Thereafter, the inner pressureof the autoclave was reduced to an atmospheric pressure. After cooling,a polyamide 612 having a terminal amino group concentration of 95mmol/kg was obtained.

The polyamide 612 was used as a hard resin to create a flat plate (rigidplastic molded article) 100 mm wide, 100 mm long and 2 mm thick by aninjection molding.

Then, about quarter area containing one side of the flat plate wascovered with aluminum foil, the flat plate was inserted or put into ametal mold for flat plate having field of 100×100 mm and depth of 4 mm,and a thermoplastic polyurethane elastomer TPU (manufactured by BASF,Elastollan ET590) as an on rigid (or flexible) plastic wasinjection-molded to the metal mold. The injection molding of the TPU wasconducted under the condition that the cylinder temperature and themetal mold temperature were 205° C. and 60° C., respectively. Thusobtained molded composite article was cut into a size of 20 mm in widthto give a test piece having an end separated by aluminum foil betweenthe polyamide resin layer (member) and the TPU layer (member). The testpiece was peeled to separate the polyamide resin layer from the TPUlayer using the end separated by the aluminum foil as tong hold.Measured peel strength was 90 N/cm.

Example 2

(1) Preparation of Polyamide Oligomer

An autoclave was substituted with nitrogen gas, and 1,000 g oflauryllactam and 230 g of dodecanediamine were added thereto. Theresulting mixture was stirred with heating. The reaction system wasgradually pressurized, maintained to 17.5 kgf/cm² (1.7×10⁶ Pa) at 270°C., and stirred for about 2 hours under heating. Then, the reactionsystem was cooled with gradually reducing the pressure to an atmosphericpressure, a polyamide 12 oligomer was taken out in a molten form. Theresulting polyamide 12 was further cooled to give a slightly fragilesolid. The number average molecular weight of the polyamide 12 oligomerwas as low as about 5500. The content of the amino group in the oligomerwas 400 mmol/kg.

(2) Preparation of Base Polyamide

Lauryllactam (800 g) and dodecanoic diacid (90 g) were added into apressure vessel, and stirred at 270° C. and 20 atmosphere (about 2 MPa)for 3 hours under nitrogen gas flow. A polytetramethylene ether glycol(which has a number average molecular weight of 1300 and hydroxyl groupsas both ends) (320 g) was added to thus obtained mixture, and stirredwith heating under a reduced pressure. After 5 hours, a polyamideelastomer (having a terminal amino group concentration of 4 mmol/kg) tobe a polyamide block copolymer was obtained.

(3) Production of Molded Composite Article

The polyamide 12 oligomer obtained from the above-mentioned item (1) wasmixed with the polyamide elastomer obtained from the above-mentioneditem (2) by a biaxial extruder at a proportion of 5 parts by weight ofthe polyamide 12 oligomer relative to the 100 parts by weight of thepolyamide elastomer, and the mixture was pelletized to give a rigidplastic having a terminal amino group concentration of 20 mmol/kg.

Then, a thermoplastic polyurethane elastomer TPU (manufactured by BASF,Elastollan S95) as an on rigid plastic was injection-molded to create aflat plate (nonrigid plastic molded article) 100 mm wide, 100 mm longand 2 mm thick. About quarter area containing one side of the flat platewas covered with aluminum foil, the flat plate (nonrigid plastic moldedarticle) was inserted into a metal mold for flat plate having field of100×100 mm² and depth of 4 mm, and a rigid plastic was injection-molded.The injection molding of the rigid plastic was conducted under acondition that the cylinder temperature and the metal mold temperaturewere 220° C. and 60° C., respectively. Thus obtained molded compositearticle was cut into a size of 20 mm in width to give a test piecehaving an end separated by aluminum foil between the polyamide resinlayer (member) and the TPU layer (member). The test piece was peeled toseparate the polyamide resin layer from the TPU layer using the endseparated by the aluminum foil as tong hold. Measured peel strength was100 N/cm.

Example 3

In an autoclave substituted with nitrogen gas, a salt (1000 g) ofbis(4-aminocyclohexyl)methane and dodecanedicarboxylic acid was heatedat 220° C. under an applied pressure (inner pressure) (17.5 kgf/cm²(1.7×10⁶ Pa)), and water in the reaction system was discharged with thenitrogen gas from the reaction system for 4 hours. Subsequently, thetemperature of the system was gradually increased up to 275° C. over 1hour, and residual water was removed. Thereafter, the inner pressure ofthe autoclave was reduced to an atmospheric pressure. After cooling, atransparent polyamide having a terminal amino group concentration of 30mmol/kg was obtained.

The transparent polyamide was used as a rigid plastic to create a flatplate (rigid plastic molded article) 100 mm width, 100 mm long and 2 mmthick by an injection molding.

The heat of crystallization and the heat of fusion of the transparentpolyamide flat plate was measured at a heating speed of 10° C./min. by aDSC analysis apparatus to show a heat of crystallization ΔHf of 11 J/gnear 170° C., and a heat of fusion ΔHm of 25 J/g near 250° C. Based onthe heat of crystallization and heat of fusion, the enthalpies of fusionand crystallization of the molded article was determined as 14 J/g.

Then, about quarter area containing one side of the flat plate wascovered with aluminum foil, the flat plate (rigid plastic moldedarticle) was inserted or put into a metal mold for flat plate havingfield of 100×100 mm² and depth of 4 mm, and a thermoplastic polyurethaneelastomer TPU (manufactured by BASF, Elastollan 1195ATR) as a nonrigidplastic was molded or injection-molded to the metal mold. The injectionmolding of the TPU was conducted under a condition that the cylindertemperature and the metal mold temperature were 205° C. and 60° C.,respectively. Thus obtained molded composite article was cut into a sizeof 20 mm in width to give a test piece having an end separated byaluminum foil between the polyamide resin layer (member) and the TPUlayer (member). The test piece was peeled to separate the polyamideresin layer from the TPU layer using the end separated by the aluminumfoil as tong hold. Measured peel strength was 130 N/cm.

Example 4

In the presence of a small amount of phosphoric acid, ω-lauryllactam(1000 g) was heated at a temperature of about 250 to 260° C. in anautoclave substituted with nitrogen gas, and water in the system wasdischarged outside of the system with nitrogen gas for 4 hours.Subsequently, the temperature of the system was gradually increased upto 275° C. over 1 hour, and water remaining in the system was removedout of the system. After cooling, a polyamide 12 having a terminal aminogroup concentration of 30 mmol/kg was obtained.

A molded composite article was produced in the same manner as in Example3 except for using the polyamide 12 as a rigid plastic. The moldedcomposite article had the enthalpies of fusion and crystallization ofthe rigid plastic molded article of 65 J/g and the peel strength of 60N/cm.

Comparative Example 1

A polyamide 612 was obtained in the same manner as in Example 1 exceptthat dodecanedicarboxylic acid (15 g) instead of hexamethylenediaminewas added to the aqueous solution containing a salt ofhexamethylenediamine with dodecanedicarboxylic acid in a concentrationof 80% by weight. The resulting polyamide 612 had a terminal amino groupconcentration of 7 mmol/kg.

A molded composite article was produced in the same manner as in Example1 except for using the polyamide 612 as a rigid plastic. The peelstrength of the molded article was 5 N/cm.

Comparative Example 2

A molded composite article was obtained as the same manner as in Example2 except that the polyamide elastomer (having a terminal amino groupcontent of 4 mmol/kg) of Example 2 was used alone as a rigid plasticwithout mixing the oligomer. The molded composite article had the peelstrength of 30 N/cm.

Examples 5 to 19 and Comparative Examples 3 to 6

(1) Preparation of Polyamide-Series Resin

A polyamide, a polyamide oligomer, and a polyamide blend were preparedaccording to the following procedures.

(A1) PA12

ω-lauryllactam (1000 g) and dodecanedicarboxylic acid (10 g) were heatedat 250 to 260° C. in the presence of a small amount of phosphoric acidin an autoclave substituted with nitrogen gas to discharge water in thesystem together with nitrogen gas over 4 hours. Subsequently, thetemperature of the system was gradually increased up to 275° C. over 1hour to remove residual water out of the system, and the system wascooled to give a polyamide 12 (A1) having an amino group concentrationof 7 mmol/kg, and a carboxyl group concentration of 81 mmol/kg.

(A2) PA12

A polyamide 12 (A2) was obtained by operating in the same manner as inthe case of the above-mentioned (A1) except for usinghexamethylenediamine (60 g) instead of dodecanedicarboxylic acid, andthe polyamide 12 (A2) had an amino group concentration of 72 mmol/kg anda carboxyl group concentration of 4 mmol/kg.

(A3) PA612

To an aqueous solution (1250 g) containing a salt ofhexamethylenediamine with dodecanedicarboxylic acid in a concentrationof 80% by weight was added 5 g of dodecanedicarboxylic acid. Theresulting mixture was heated at 220° C. under an applied pressure (innerpressure) (17.5 kgf/cm² (1.7×10⁶ Pa)) in an autoclave substituted withnitrogen gas, and water was flowed out with the nitrogen gas from thereaction system for 4 hours. Subsequently, the temperature of the systemwas gradually increased up to 275° C. over 1 hour, and water remainingin the system was removed out of the system. Thereafter, the innerpressure of the autoclave was reduced to be an atmospheric pressure.After cooling, a polyamide 612 (A3) having an amino group concentrationof 4 mmol/kg and a carboxyl group concentration of 35 mmol/kg wasobtained.

(A4) PA612

By operating in the same manner as in Example 1, and a polyamide 612(A4) was obtained having an amino group concentration of 97 mmol/kg anda carboxyl group concentration of 27 mmol/kg.

(A5) Polyamide Elastomer PAE

In the same manner as in the preparation (2) of Example 2, a polyamideelastomer (A5) having an amino group concentration of 4 mmol/kg and acarboxyl group concentration of 50 mmol/kg was obtained.

(A6) PA6

ε-caprolactam (1000 g) and hexamethylenediamine (100 g) were heated at270 to 280° C. in the presence of a small amount of phosphoric acid inan autoclave substituted with nitrogen gas to discharge water in thesystem together with nitrogen gas over 5 hours. Then, the system wascooled to give a polyamide 6 (A6) having an amino group concentration of103 mmol/kg, and a carboxyl group concentration of 45 mmol/kg.

(A7) Alicyclic Polyamide

An alicyclic polyamide (A7) was prepared in the same manner as in thecase of the above-mentioned (A3) except thatbis(4-aminocyclohexyl)methane and dodecanedicarboxylic acid were used asa monomer component and that dodecanedicarboxylic acid was not added tothe system. The resulting alicyclic polyamide (A7) had an amino groupconcentration of 42 mmol/kg and a carboxyl group concentration of 78mmol/kg.

(OL) Polyamide Oligomer

A polyamide oligomer (OL) was prepared in the same manner as in Example2 (1). Thus obtained polyamide oligomer (OL) had a number averagemolecular weight of about 5700, an amino group content of 342 mmol/kg,and a carboxyl group content of 0 mmol/kg.

(Polyamide Blend)

Components shown in Table 1 (the polyamide resins, the polyamideelastomer and the polyamide oligomer, each obtained by theabove-mentioned manner) were mixed at a mixing ratio (weight ratio)shown in Table 1 to prepare sample resins (polyamide resin blends) bykneading with a biaxial extruder. The sample resins were different inamino group concentration from each other.

(2) Production of Molded Composite Article, and Peeling Test Thereof

A molded composite article was formed with the polyamide-series resin(PA) shown in Table 1, and a thermoplastic polyurethane elastomer TPU(manufactured by BASF, S95). The molded article was cut into a size of20 mm in width, and the end of the molded composite article wasseparated by aluminum foil. The separated ends of the PA member (layer)and the TPU member (layer) were used as tong holds, and the peeling testwas conducted.

Incidentally, the molded composite article was formed by covering aboutquarter area containing one side of a molded article formed with apolyamide-series resin (flat plate 100 mm wide, 100 mm long and 2 mmthick, formed by an injection molding) with aluminum foil, and puttingor setting the resin member into a metal mold for flat plate havingfield of 100×100 mm² and depth of 4 mm, and injecting orinjection-molding the TPU in the metal mold. The injection molding ofthe TPU was carried out under a condition that the cylinder temperatureand the metal mold temperature were 205° C. and 60° C., respectively.

The results are shown in Table 1. TABLE 1 Content of terminal group(mmol/kg) Peeling Carboxyl Amino strength Polyamide resin group group(N/cm) Com. Ex. 3 PA12 A1 81 7 24 Ex. 5 A1/A2 = 75/25 64 24 90 Ex. 6A1/A2 = 50/50 43 40 115 Ex. 7 A2 4 72 130 Com. Ex. 4 A1/OL = 81 9 2699.5/0.5 Ex. 8 A1/OL = 97/3 79 17 65 Ex. 9 A1/OL = 95/5 77 24 95 Com.Ex. 5 PA612 A3 35 4 10 Ex. 10 A3/A4 = 75/25 33 27 75 Ex. 11 A3/A4 =50/50 31 51 100 Ex. 12 A4 27 97 110 Ex. 13 A3/OL = 95/5 33 21 80 Com.Ex. 6 PAE A5 50 4 21 Ex. 14 A5/OL = 98/2 49 15 103 Ex. 15 A5/OL = 95/548 21 104 Ex. 16 A5/OL = 90/10 45 38 110 Ex. 17 PA6 A6 45 103 110 Ex. 18Alicyclic A7 78 42 140 Ex. 19 PA A7/OL = 90/10 70 72 145

Incidentally, in the case where a molded composite article was producedin the same manner as described above except that the molded article(resin member) formed with the TPU was used instead of the resin memberformed with the polyamide-series resin, and that the injection moldingwas conducted by using a polyamide-series resin A3/A4 (75/25), A3/A4(50/50), or A4, instead of the TPU for injection molding, peel strengthof the resulting molded composite article was 95 N/cm (A3/A4=75/25), 130N/cm (A3/A4=50/50), or 150 N/cm (A4).

Example 20 and Comparative Example 7

Molded composite articles were produced in the same manner as in Example5 except that resin members formed with various thermoplasticpolyurethane elastomers (TPU) shown in Table 2 were used instead of theresin member formed with the polyamide-series resin, and that thepolyamide resins A1 and A2 obtained in Example 5 were used inComparative Example 7 and Example 20, respectively, instead of the TPUfor injection molding. The peeling test was conducted, and the resultsare shown in Table 2. Incidentally, Table 2 also shows the Shore Ahardness and type of the used TPU. TABLE 2 Manufac- Peeling strength(N/m) turing cor- Shore A Ex. 20 Com. Ex. 7 porations Grade hardnessType (A2) (A1) BASF S95 95 Ester 123  24 1195 95 Ether 129  28 C90 90Ester (water 84 22 resistant type) ET590 90 Ester >150*⁾  19(transparent type) ET690 90 Ester (for 90 28 injection) ET885 85 Ether(for 97 27 injection, cold resis- tant type) Nippon E580 80 Ester 90 7Polyurethane E980 80 Carbonate 65 6 Industry E380 80 Ether >150*⁾  16Co., Ltd.In Table, the symbol “*” indicates that the slight peeling was observedand the substrate (A2 or TPU) was broken.

Examples 21 to 25

(1) Preparation of Base Polyamide (Polyamide Elastomer (A8))

In a pressure vessel, lauryllactam (800 g) and dodecanoic diacid (90 g)were added, and stirred at 270° C. and 20 atmospheres (about 2 MPa) for3 hours under nitrogen gas flow. A polytetramethylene ether glycol(having a number average molecular weight of 1300 and a terminalhydroxyl group) (290 g) was added to the resulting mixture, and heatedand stirred under a reduced pressure. After 5 hours, a polyamideelastomer (A8) having an amino group concentration of 4 mmol/kg and acarboxyl group concentration of 50 mmol/kg was obtained.

(2) Production of Molded Composite Article, and Peeling Test Thereof

The polyamide elastomer (A8) and the polyamide oligomer (OL) describedin the paragraph of Examples 5 to 19 were used at a mixing ratio [theformer/the latter] of 100/5 (weight ratio), and were kneaded by abiaxial extruder to prepare a sample resin (polyamide resin blend)having a terminal carboxyl group concentration of 40 mmol/kg and aterminal amino group concentration of 25 mmol/kg.

A molded composite article was formed with thus obtainedpolyamide-series resin (PA) and the TPU shown in Table 3. The moldedcomposite article was cut into a size of 20 mm in width, and the end ofthe molded composite article was separated by aluminum foil. Theseparated ends of the PA member (layer) and the TPU member (layer) wereused as tong holds, and the peeling test was conducted. As the TPU, anester-series TPU (manufactured by BASF, 195-50ET) and an ether-seriesTPU (manufactured by BASF, ET890-10) were used.

Incidentally, the molded composite article was formed by covering aboutquarter area containing one side of a molded article formed with the TPU(a flat plate 100 mm wide, 100 mm long and 2 mm thick, formed by aninjection molding) with aluminum foil, and inserting the resin memberinto a metal mold for flat plate having field of 100×100 mm² and depthof 4 mm, and injecting or injection-molding the PA in the metal mold.The injection molding of the PA was carried out under a condition of ajoining temperature (cylinder temperature) shown in Table 3 and a metalmold temperature of 60° C.

The results are shown in Table 3. TABLE 3 Content of terminal group ofPA (mmol/kg) Joining Peeling Carboxyl Amino temperature strength groupgroup TPU (° C.) (N/cm) Ex. 21 40 25 Ester-series 230 42 (195-50ET) Ex.22 40 25 Ester-series 250 76 (195-50ET) Ex. 23 40 25 Ester-series 270 82(195-50ET) Ex. 24 40 25 Ether-series 250 58 (ET890-10) Ex. 25 40 25Ether-series 270 53 (ET890-10)

Examples 26 to 29

The polyamide elastomer (PAE) (A5) and the polyamide oligomer (OL)described in the paragraph of Examples 5 to 19 were used at a mixingratio shown in Table 4, and were kneaded by a biaxial extruder toprepare a sample resin (polyamide resin blend). The terminal carboxylgroup concentration and the terminal amino group concentration of thusobtained polyamide blend were also shown in Table 4.

A molded composite article was formed with thus obtainedpolyamide-series resin blend (PA) and the TPU shown in Table 4. Themolded composite article was cut into a size of 20 mm in width, and theend of the molded composite article was separated by aluminum foil. Theseparated ends of the PA member (layer) and the TPU member (layer) wereused as tong holds, and the peeling test was conducted.

Incidentally, the molded composite article was formed by covering aboutquarter area containing one side of a molded article formed with the TPU(a flat plate 100 mm wide, 100 mm long and 2 mm thick, formed by aninjection molding) with aluminum foil, and inserting the resin memberinto a metal mold for flat plate having field of 100×100 mm² and depthof 4 mm, and injecting or injection-molding the PA in the metal mold.The injection molding of the PA was carried out under a condition thatthe joining temperature (cylinder temperature) and the metal moldtemperature were 250° C. and 60° C., respectively. As the TPU, anester-series TPU (manufactured by BASF, 195-50ET) and an ether-seriesTPU (manufactured by BASF, ET890-10) were used.

The results are shown in Table 4. TABLE 4 Content of terminal group(mmol/kg) Peeling Carboxyl Amino strength PAE/OL group group TPU (N/cm)Ex. 26 90/10 36 40 Ether-series 88 (ET890-10) Ex. 27 80/20 29 61Ether-series 100 (ET890-10) Ex. 28 90/10 36 40 Ester-series 190(195-50ET) Ex. 29 80/20 29 61 Ester-series 110 (195-50ET)

Examples 30 to 35

(1) Preparation of base Polyamide (Polyamide Elastomer (A9))

Lauryllactam (800 g) and dodecanoic diacid (90 g) were added into apressure vessel, and stirred at 270° C. and 20 atmosphere (about 2 MPa)for 3 hours under nitrogen gas flow. A polytetramethylene ether glycol(which has a number average molecular weight of 1300 and hydroxyl groupsas both ends) (320 g) was added to thus obtained mixture, and stirredfor 5 hours with heating under a reduced pressure. After completion ofthe reaction, the reduced pressure was released. Octamethylenediamine(60 g) was further added to the vessel, and stirred at 270° C. for 1hour under an atmospheric pressure. Then, the resulting product wasgradually cooled to give a polyamide elastomer having a terminal aminogroup (having a terminal carboxyl group concentration of 12 mmol/kg anda terminal amino group concentration of 42 mmol/kg) (A9).

(2) Production of Molded Composite Article, and Peeling Test Thereof

Sample resins were prepared by kneading with a biaxial extruder with thepolyamide elastomer (A9) alone, or the mixture of the polyamideelastomer (A9), the polyamide elastomer (PAE) obtained in Example 2 andthe polyamide oligomer (OL) described in the paragraph of Examples 5 to19 at a mixing ratio (weight ratio) of PAE/A9/OL=10/80/10. Incidentally,the polyamide resin blend comprising the polyamide elastomer (PAE) andthe polyamide elastomer (A9) and the polyamide oligomer (OL) had aterminal carboxyl group concentration of 33 mmol/kg and a terminal aminogroup concentration of 46 mmol/kg.

A molded composite article was formed with thus obtained sample resin(PA) and the TPU shown in Table 5. The molded composite article was cutinto a size of 20 mm in width, and the end of the molded compositearticle was separated by aluminum foil. The separated ends of the PAmember (layer) and the TPU member (layer) were used as tong holds, andthe peeling test was conducted.

Incidentally, in Examples 30, 31, 34 and 35, the molded compositearticle was formed by covering about quarter area containing one side ofa molded article formed with the TPU (flat plate 100 mm wide, 100 mmlong and 2 mm thick, formed by an injection molding) with aluminum foil,and putting the resin member into a metal mold for flat plate havingfield of 100×100 mm and depth of 4 mm, and injecting orinjection-molding the PA in the metal mold. The injection molding of thePA was carried out under a condition that the joining temperature(cylinder temperature) and the metal mold temperature were 250° C. and60° C., respectively.

Moreover, in Examples 32 and 33, the molded composite article wasobtained in the same manner as in the above-mentioned manner except thata molded article formed with the PA was used instead of a molded articleformed with the TPU and that the injection molding was conducted byusing the TPU instead of the PA, and was subjected to a peeling test.

Incidentally, as the TPU, an ester-series TPU (manufactured by BASF,ET195) and an ether-series TPU (manufactured by BASF, ET890) were used.

The results are shown in Table 5. TABLE 5 Content of terminal group(mmol/kg) Peeling Carboxyl Amino strength PA group group TPU (N/cm) Ex.30 A9 12 42 Ester-series 125 (ET195) Ex. 31 A9 12 42 Ether-series 160(ET890) Ex. 32 A9 12 42 Ester-series 130 (ET195) Ex. 33 A9 12 42Ether-series 130 (ET890) Ex. 34 PAE/A9/OL 33 46 Ester-series 14080/10/10 (ET195) Ex. 35 PAE/A9/OL 33 46 Ether-series 95 80/10/10 (ET890)

Examples 36 to 40

(1) Preparation of Base Polyamide (Polyamide Elastomers (A10) to (A12))

Each of polyamide elastomers (A10) to (A12) was prepared in the samemanner as in the polyamide elastomer (A5) except that dodecanoic diacid(DDA) and polytetramethylene ether glycol (PTMG) were used at aproportion shown in Table 6, and thus obtained polyamide elastomers(A10) to (A12) had an amino group concentration of 4 mmol/kg. Table 6also shows the content (wt. %) of polyether segment in thus obtainedpolyamide elastomers. TABLE 6 Content of polyether segment DDA (g) PTMG(g) (wt. %) (A10) 55 214 20 (A11) 25 92 10 (A12) 10 43 5(2) Preparation of Sample Resin

A polyamide elastomer (90 parts by weight) and the polyamide oligomer(OL) used in Example 8 (10 parts by weight) were kneaded by a biaxialextruder to prepare a sample resin (Examples 36 to 39). Incidentally,the polyamide resin blends comprising the polyamide elastomer and thepolyamide oligomer (OL) had an amino group concentration of 38 mmol/kg.

Moreover, the polyamides (A1) and (A2) were used at a mix ratio of 50/50(weight ratio), and kneaded by a biaxial extruder to give a sample resin(Example 40).

(3) Peeling Test

Thus obtained sample resin (PA), and a polyether-series TPU(manufactured by BASF, ET890-10) or a polyester-series TPU (manufacturedby BASF, 195-50ET) were employed to form a molded composite article. Thecomposite article was cut into a size of 20 mm in width, and the end ofthe molded composite article was separated by aluminum foil. Theseparated ends of the PA member (layer) and the TPU member (layer) wereused as tong holds, and the peeling test was conducted.

Incidentally, the molded composite article was formed by covering aboutquarter area containing one side of a molded article formed with the TPU(a flat plate 100 mm wide, 100 mm long and 2 mm thick, formed by aninjection molding) with aluminum foil, and inserting this resin memberinto a metal mold for flat plate having field of 100×100 mm² and depthof 4 mm, and injecting or injection-molding the PA in the metal mold.The injection molding of the PA was carried out under a condition of ajoining temperature (cylinder temperature) of 250° C. and a metal moldtemperature of 60° C.

The results are shown in Table 7. Further, Table 7 also shows thecontent (wt. %) of the polyether segment in the polyamide elastomer orpolyamide, and the melting point of the polyamide elastomer orpolyamide. TABLE 7 Polyamide elastomer or Peeling polyamide strength(N/cm) Content of Ether- Ester- PA (mix polyether Melting series seriesratio) segment (wt. %) point (° C.) TPU TPU Ex. 36 A5/OL 26 169 94 11690/10 Ex. 37 A10/OL 20 171 101 108 90/10 Ex. 38 A11/OL 10 176 82 9290/10 Ex. 39 A12/OL 5 177 70 85 90/10 Ex. 40 A1/A2 0 178 72 85 50/50

Example 41 Measurement of Warp

The polyether-series TPU (manufactured by BASF, ET890-10) was employedto create a flat plate 100 mm wide, 100 mm long and 2 mm thick by aninjection molding. Then, the TPU flat plate was inserted or placed intoa metal mold for flat plate having field of 100×100 mm² and depth of 4mm, and the PA (polyamide elastomer or polyamide) shown in Table 8 wasinjection-molded to the metal mold to give a molded composite article.Incidentally, the injection molding of the PA was conducted under acondition that the metal mold temperature and the temperature of theinjected PA resin were 60° C. and 250° C., respectively.

Thus obtained molded composite article was cut into a size of 20 mm inwidth to create a test sample. In thus obtained sample, the PA layer wasconstricted, the TPU layer was elongated, and the sample was curved tothe longitudinal direction. The TPU layer in one end of the longitudinaldirection of the sample was fixed to a surface plate, and the distancebetween the hemline of the other end and the surface plate was measuredand determined as a warp degree.

The results are shown in Table 8. Table 8 also includes the content ofthe polyether segment in the polyamide elastomer or polyamide, and thefinal crystallinity degree. Incidentally, the final crystallinity degreewas measured according to the above-mentioned method. TABLE 8 PA A5 A10A11 A12 A2 Content of polyether 26 20 10 5 0 segment (wt. %) Finalcrystallinity 30 35 40 42 45 degree (%) Warp (mm) 7 8 10 15 18

1. A molded composite article which comprises (Ia) a resin membercomprising a polyamide-series resin and (IIa) a resin member comprisinga thermoplastic polyurethane-series resin, wherein the resin member (Ia)is directly joined or bonded to the resin member (IIa), and thepolyamide-series resin has an amino group in a proportion of not lessthan 10 mmol/kg.
 2. A molded composite article according to claim 1,wherein the polyamide-series resin constituting the resin member (Ia) isthe following resin (A) or (B): (A) a polyamide-series resin which is(Ib-1) a single polyamide-series resin, or (Ib-2) a mixture of aplurality of polyamide-series resins each having different amino groupcontent from each other, and which has an amino group in a proportion ofnot less than 20 mmol/kg, (B) a polyamide-series resin which is (Ib-3) aresin composition containing a polyamide-series resin and a compoundhaving an amino group, and which has an amino group in a proportion ofnot less than 10 mmol/kg.
 3. A molded composite article according toclaim 1, wherein the polyamide-series resin constituting the resinmember (Ia) comprises at least one member selected from the groupconsisting of an aliphatic polyamide-series resin, an alicyclicpolyamide-series resin, an aromatic polyamide-series resin, and apolyamide block copolymer.
 4. A molded composite article according toclaim 2, wherein, in the resin composition (Ib-3), the compound havingan amino group comprises at least one member selected from the groupconsisting of a monoamine, a polyamine, and a polyamide oligomer.
 5. Amolded composite article according to claim 2, wherein, in the resincomposition (Ib-3), the proportion of the compound having an amino groupis 0.01 to 10 parts by weight relative to 100 parts by weight of thebase polyamide-series resin.
 6. A molded composite article according toclaim 1, wherein the polyamide-series resin constituting the resinmember (Ia) comprises a polyamide oligomer, and at least one basepolyamide resin selected from the group consisting of an aliphaticpolyamide-series resin, an alicyclic polyamide-series resin, and apolyamide block copolymer.
 7. A molded composite article according toclaim 1, wherein the thermoplastic polyurethane-series resin comprises athermoplastic polyurethane elastomer.
 8. A molded composite articleaccording to claim 1, wherein the polyamide-series resin has a terminalamino group, and the thermoplastic polyurethane-series resin comprises apolyester polyurethane containing a polyester diol as a constitutiveunit.
 9. A molded composite article according to claim 1, wherein thepolyamide-series resin constituting the resin member (Ia) comprises atleast one member selected from the group consisting of an aliphaticpolyamide-series resin, an alicyclic polyamide-series resin, and anaromatic polyamide-series resin, and the thermoplasticpolyurethane-series resin comprises at least one member selected fromthe group consisting of a polyether urethane elastomer, a polyesterether urethane elastomer, and a polycarbonate urethane elastomer.
 10. Amolded composite article according to claim 1, wherein thepolyamide-series resin constituting the resin member (Ia) comprises atleast a polyamide block copolymer, and the thermoplasticpolyurethane-series resin comprises at least one member selected fromthe group consisting of a polyether urethane elastomer, a polyesterurethane elastomer, a polyester ether urethane elastomer, and apolycarbonate urethane elastomer.
 11. A molded composite articleaccording to claim 9, claim 10 wherein the polyamide block copolymer isa polyamide elastomer having in a molecule thereof at least one memberselected from the group consisting of a polyether segment, a polyestersegment, and a polycarbonate segment.
 12. A molded composite articleaccording to claim 1, which is a member of a shoe or a roll.
 13. Aprocess for producing a molded composite article recited in claim 1,which comprises heating at least one resin selected from the groupconsisting of (Ib) a resin comprising a polyamide-series resin recitedin claim 1 and (IIb) a resin comprising a thermoplasticpolyurethane-series resin to join one resin to the other resin.
 14. Aprocess according to claim 13, wherein the thermoplasticpolyurethane-series resin is melted or fused under heating, and themolten thermoplastic polyurethane-series resin is brought into contactwith at least part of a resin member comprising the polyamide-seriesresin for uniting both resins.
 15. A process according to claim 13,wherein the polyamide-series resin is melted or fused under heating, andthe molten polyamide-series resin is brought into contact with at leastpart of a resin member comprising the thermoplastic polyurethane-seriesresin for uniting both resins.
 16. A process according to claim 13,wherein the polyamide-series resin and the thermoplasticpolyurethane-series resin are independently melted or fused underheating, and the molten polyamide-series resin is brought into contactwith the molten thermoplastic polyurethane-series resin for uniting bothresins.
 17. A process according to claim 13, wherein thepolyamide-series resin and the thermoplastic polyurethane-series resinare joined and united by a molding method selected from the groupconsisting of a thermoforming, an injection molding, an extrusionmolding, and a blow molding.